The Gordon Research Conference on Diffraction Methods in Molecular Biology is an ongoing biannual meeting at which the latest results and methods of macro-molecular crystallography are discussed in depth. Since its inception over 25 years ago, this field has been and continues to be at the forefront of structural biology. The systems being studied by the participants in this Conference, who are the leaders of their fields, bear on a variety of health-related areas. Much of the subject research is supported by the NIH. This application is for partial support of the next Diffraction Methods Gordon Conference. The planned program highlights the leading edge of the field today by emphasizing 1) areas where groups of newly determined structures are answering important biological questions, 2) breakthroughs in technology for obtaining more accurate data more rapidly, and 3) examples of the increasing interdependence of crystallography and other methodologies for the study of structure.